This disclosure relates generally to multi-band antenna assemblies, and more particularly to extending a single dual-band planar antenna structure to cover additional bands.
In order to create an antenna that operates in multiple frequency bands, manufacturers often had to switch between two or more separate antenna structures. For example, in the mobile telephone field, a first dual band antenna is used for U.S. bands GSM 850 (824-894 MHz) and PCS 1900 (1850-1990 MHz) while a second dual band antenna is used for European bands E-GSM 900 (880-960 MHz) and DCS 1800 (1710-1880 MHz). By switching between two dual-band antenna structures in a mobile telephone, a user could communicate on all four bands (GSM 850, E-GSM 900, DCS 1800, and PCS 1900). Alternately, a mobile telephone could have one dual-band antenna structure and a single band antenna structure where the interaction of one or more of the antenna structures produces operation in up to four bands. Including two antenna structures in a mobile telephone, however, creates a larger antenna assembly, which can be undesirable from a user""s standpoint.
Additionally, the option of two dual-band antenna structures complicates manufacturing and inventory processes even when manufacturing only for two bands, because the manufacturer needs to select one dual-band antenna for a mobile telephone that will operate only in the U.S. GSM bands and another dual-band antenna for a mobile telephone that will operate only in the European GSM bands.
Thus, there is a need for a multi-band antenna assembly that does not involve two or more separate antenna structures. There is also a need for a multi-band antenna assembly that allows variations in the bands to improve tuning and coverage.
The various aspects, features and advantages of the disclosure will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Drawings and accompanying Detailed Description.
FIG. 1 shows a distributed equivalent circuit model for a variable multi-band planar antenna assembly.
FIG. 2 shows a top view of a variable multi-band planar antenna assembly according to a first preferred embodiment.
FIG. 3 shows a side view of a variable multi-band planar antenna assembly according to the first preferred embodiment.
FIG. 4 shows a lumped electrical equivalent element model for a variable multi-band planar antenna assembly.
FIG. 5 shows return losses for the first preferred embodiment shown in FIGS. 2 and 3.
FIG. 6 shows additional return losses for the first preferred embodiment shown in FIGS. 2 and 3.
FIG. 7 shows a top view of a variable multi-band planar antenna assembly according to a second preferred embodiment.
FIG. 8 shows return losses for the second preferred embodiment shown in FIG. 7.
FIG. 9 shows a top view of a variable multi-band planar antenna assembly according to a third preferred embodiment.
FIG. 10 shows a top view of a variable multi-band planar antenna assembly according to a fourth preferred embodiment.
FIG. 11 shows return losses for the fourth preferred embodiment shown in FIG. 10.
FIG. 12 shows an implementation of a variable multi-band planar antenna assembly in accordance with the first preferred embodiment in a wireless communication device such as a mobile telephone.
FIG. 13 shows a side view of a variable multi-band planar antenna assembly according to a fifth preferred embodiment.
FIG. 14 shows a top view of a variable multi-band planar antenna assembly according to a sixth preferred embodiment.
FIG. 15 shows a top view of a variable multi-band planar antenna assembly according to a seventh preferred embodiment.
FIG. 16 shows a top view of a variable multi-band planar antenna assembly according to an eighth preferred embodiment.